Farmers Weekly Interactive

West: BYDV back with a vengeance

Barley yellow dwarf virus has started to show up in many crops in the last month. It has been several years since we have seen a widespread infection of this aphid-borne viral disease.

At the moment it seems to be limited to barley, but the disease does not tend to show wheat and oats until later. Even some crops planted with Deter-treated seed are affected, though symptoms are mild.

Early planted barley crops without Deter seed dressing have been most severely affected, even where well timed aphicide applications were made last autumn. This suggests either carryover of aphids from the previous crop or infection from migratory aphids that moved into the new crop very early.

In the west of the region I have seen pockets of yellow rust infection in
wheat. A robust T0 application has been applied and appears to have halted
development of the disease. These crops will require careful monitoring to make
sure that we have caught it early enough.

At the start of the week most barley crops were at GS 32 and developing
quite quickly. Most crops have now received their T1 fungicide.

Most wheat crops are rapidly approaching GS32, so weather permitting many
crops will receive their T1 fungicide this week.

As usual in the south west Septoria tritici will be the primary target. Some
highest potential crops will receive an SDHI as there is likely to be at least
four weeks until T2 in mid May – being in a mild area GS 32 is reached early
but the flag leaf rarely emerges any sooner than elsewhere.

Rape crops are looking fairly clean and are slowly coming into full flower. Pollen
beetle has been more prevalent but only a couple of crops have achieved
threshold.

Spring barleys drilled into good seedbeds have emerged well and are looking
full of potential. Some crops have however been drilled into dry and cloddy
seedbeds and are going to struggle as a result.

Maize drilling has begun even though soil temperatures are only just getting
where they need to be. The memory of last years’poorly established crops, due
to drought, appears to be the stimulus.

Neil Potts

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